During the last year our research core has worked with ten NIH research units to generate novel embryonic stem cell lines (26 projects) and new mouse models (29 projects). This research included establishment of models to study disease associated with RNAse H dysfunction, signal pathway interactions in the immune system, T cell development, hematopoiesis, stem cell biology, epigenetic inheritance in the early embryo, RNA metabolism, genetic disorders in bone and extracellular matrix, gene regulation and enhancer function, and endocrine and cancer genetics. We also performed cryopreservation of 9 mouse lines, derived 6 novel embryonic stem cell lines from genetically altered mice, and re-derived 6 mouse strains. In the past year we have developed the capability to perform zygote injections (nuclear and cytoplasmic) and will be offering these services to the research community in 2018.